Gardiner is an unincorporated community and census-designated place in Douglas County, Oregon, United States, across the Umpqua River from Reedsport. It is located on U.S. Route 101. As of the 2010 census, it had a population of 248.Gardiner is named for a Boston merchant whose ship, the Bostonian, shipwrecked at the mouth of the Umpqua on October 1, 1850. Gardiner was seeking to trade along the river, and most of his goods were saved from the ship and moved to the location that came to be the town of Gardiner. In 1851, the site became the headquarters of the Umpqua customs district, and a post office named "Gardiners City" was established the same year. The name of the post office changed to "Gardiner City" and eventually to its current name.The Gardiner Historic District, which encompasses nearly all of Gardiner, has been listed on the National Register of Historic Places since 1994. Several steamboats were constructed at Gardiner for trade up the Umpqua River.